1. Field of the Invention
The present invention relates to an apparatus for jetting ink of an ink-jet print head, and more particularly, to an apparatus for jetting ink by utilizing lamb wave and manufacturing the same.
2. Description of the Prior Art
An apparatus for jetting ink applied to a conventional ink-jet print head ejects a desired amount of the ink through a nozzle by exerting a physical force to the ink received in an ink chamber. Generally, such apparatuses are grouped by the type of system used to eject the ink, for example a piezoelectric system, a thermal system, and an electromagnetic system, etc.
Companies such as Canon and Hewlett-Packard Co. are well known for providing thermal print heads. As shown in FIG. 1, the thermal print head includes a lower insulating layer 14, a heating element 16, electrodes 18, an upper insulating layer 20, and a protecting layer 22 which are sequentially stacked on a printed circuit board (PCB) 12. Passage walls 23 are installed between a nozzle plate 24 and the protecting layer 22 to form an ink chamber 26. The ink chamber 26 is connected to a reservoir (not shown), and both electrodes 18 are connected to a driving signal generator 28.
When the driving signal generator 28 applies a driving signal to the electrodes 18, the heating element 16 is heated, and ink 27 within the ink chamber 26 is boiled. At this time, bubbles 29 are produced within the ink chamber 26, and the bubbles 29 push the ink 27 out of a nozzle 25 of the nozzle plate 24, thereby producing an ink jet 30.
Companies such as Epson are well known for providing piezoelectric print heads. As shown in FIG. 2, a piezoelectric print head includes a PCB 42, a diaphragm 44, a piezoelectric element 46, a spacer 48 and a nozzle plate 50. An ink chamber 54 is formed by the diaphragm 44, the piezoelectric element 46 and the nozzle plate 50. The interior of the ink chamber 54 is filled with ink 53. When the driving signal generator 52 applies a driving signal to the piezoelectric element, the piezoelectric element 46 mechanically expands and contracts. The expanding and contracting action of the piezoelectric element 46 causes the ink within the ink chamber 54 to be ejected from the nozzle 51, thereby producing an ink jet 55.
An electro-magnetic print head includes a magnet driver attached to an outer side of a nozzle, and a magnetically active diaphragm plate for sealing an ink chamber. The ink is ejected by a pressure which is exerted when the magnetically active diaphragm plate is deformed by a magnetic field generated by the magnet driver.
Although conventional print heads are generally thought to be acceptable, they are not without shortcomings. Specifically, piezoelectric print heads are expensive and have a complex structure. Thermal print heads are slow because of the time required to heat the ink, and the heating process deteriorates the ink. Further, the thermal print head has a complex structure making production difficult thus deteriorating the productivity. Finally, an electro-magnetic print head has a lower print quality than the other types of print heads because an induction current causes ink to be inadvertently ejected out of nozzles which are adjacent to the nozzles through which ink is intended to be ejected from.